In the present state of art, the fitting and tensioning of screen mats, cloth or others when used in vibrating or shaking machines, not only the whole crushing-screening plant must be stopped, but it is also necessary to enter inside the vibrating or shaking machine for the removal of used or damaged and then the fitting and tensioning of new screen mats, cloths or others, as well as to put back all the fitting and tensioning elements that include the tension bars, bolts, nuts and counter nuts, etc.
One must note, that in most cases, vibrating or shaking machines are made with several decks comprising several screen mats, cloths or others per deck and that the space between decks is very limited.
The change of screen mats, cloths or others is rather long, tiresome and costly in terms of loss of production and immobilization of labor. When fitting or removing new or used screen mats, cloths, or others, the presence of a person is indispensable inside the vibrating or shaking machine for at least to remove and replace the tension bars from and into the tension hooks, to remove and replace through the holes in the tension bars and in the flanges of the vibrating or shaking machine the tension bolts, to maintain these elements while from the outside of the vibrating or shaking machine, one or several persons will screw the nuts and counter nuts onto the tension bolts.
Vibrating or shaking machines currently used in mines, quarries, sand and gravel pits, etc., are not provided with systems that will avoid the inconveniences above mentioned. In all cases, the tension bars and bolts fall into the vibrating or shaking machine, when refitted, tension hooks are clamped onto the camber frame for one by the proper weight of the tension bars,and because of the pull and tension angle of the tension bolts and the pressure exercised on them at the moment of tensioning the screen mats, cloths or others.
The correct tensioning is equally not assured because of the clamping of the tension hooks over the camber frame, thus resulting a rigid fitting and tensioning without the possibility of taking up the natural lengthening of the screen mats, cloths, or others after a few hours or days of functioning. It is then necessary to stop the installation from time to time to retighten the screen mats, cloths or others.